Cy 3 and Cy 5 are the most commonly used cyan dyes for the detection of two colors. Cy3 dye is fluorescent orange, while Cy5 is fluorescent in the red region. Cyanine belongs to polymethyl group. Cy dyes are a family of fluorophores that can be used to label proteins, peptides, DNA, RNA and other biomolecules. These dyes are small in size, pH-insensitive, soluble in aqueous solutions, and resistant to DMSO. They have higher photostability, higher molar extinction coefficient and good quantum yield than fluorescein. Cy3 and Cy5 are mainly used in many different biological analysis, such as DNA microarray, protein microarray, two-dimensional protein analysis ( 2D gel ), fluorescence resonance energy transfer ( FRET ) and immunocytochemistry.
